2.0 Analysis 2.1 Introduction The investigation established that the VHF radios in the aircraft and de-icing vehicles functioned normally during the de-icing and at the time of the accident. However, there was a lack of communication between the flight crew and Snowman1 that resulted in the captain believing that the de-icing was completed. The analysis will examine the reasons why the flight crew believed that the de-icing equipment and personnel were clear of the aircraft, the lack of positive procedures on the part of the de-icing crew, and the contributing factors which led to the accident. 2.2 Decision to Taxi The flight crew did not realize that 130.775 MHz was the CAIL working frequency. They mistakenly concluded that this frequency was reserved for de-icing. In addition, the pilots assumed that 130.775 MHz was a communication system analogous to the interphone, although the frequencies used for air-ground communications are in the VHF band, 118-136MHz. Consequently, the pilots presumed that the Iceman's message about the completion of de-icing came from Snowman1, that the message was intended for them, and that it indicated that de-icing was completed. The pilots heard the words dgivrage termin (de-icing completed). Although this message was not preceded by the flight call-sign or the de-icing crew call-sign, the pilot read back de-icing completed twice. As the duration of the operation up to that point matched the time usually required for this type of de-icing, and as they received no acknowledgement from Snowman1, the flight crew thought the de-icing crew had left the frequency and departed the area. The co-pilot then advised the apron controller that the aircraft was ready to taxi, and, in doing so, the co-pilot conveyed to the apron controller that de-icing was completed and the aircraft was clear. Relying on that information, the controller indicated to the co-pilot his assigned route for taxiing from his current parking spot to Kilo turn-off. The pilot mistakenly interpreted the issuance of taxi instructions as confirmation that the aircraft was clear. According to the rules of standard phraseology, to avoid confusion, radio messages must be preceded by the receiving station call-sign, followed by the sending station call-sign. While these rules may not apply to interphone communications, the open nature of VHF radio communications requires that the international rules of radio procedure be followed. In this case, the pilot heard the words dgivrage termin and made a number of erroneous assumptions: that the radio transmission was directed to him; that the de-icing operation was completed; and that all equipment and personnel were clear of the aircraft's taxi path. 2.3 Communications Equipment Except for the background noise of the engines on the interphone, communications between the drivers and cherry-picker operators were clear. During the de-icing, the Iceman and the pilot tried without success to communicate with the de-icing crew on the CAIL frequency. By all indications, the noise of the engines prevented Snowman1 from hearing the pilot and the Iceman when they tried to communicate with him. The fact that the truck drivers did not hear these messages attests to the ineffectiveness of the vehicles' communication systems in blocking out the noise of the engines. 2.4 Regulatory Framework for Foreign Air Carriers Transport Canada certified and controlled foreign air carriers in accordance with standards different from those applicable to Canadian air carriers. Canadian air carriers were required to comply with section 540 of the Air Regulations and with ANO, Series VII, No.2. Foreign air carriers were not subject to the provisions of ANO, Series VII, No.2. Consequently, Royal Air Maroc was not required to develop a program of procedures for de-icing aircraft on the ground, although it operated its aircraft in the same environmental conditions as Canadian air carriers. Since, in accordance with ANO, Series VII, No.2, air carriers were responsible for implementing their de-icing procedures, it was not necessary to regulate the services provided by de-icing contractors. Air carriers were responsible for the safety and effectiveness of de-icing operations. As Royal Air Maroc had neither an approved ground icing operations program nor de-icing procedures, it relied on Canadian Airlines International in regard to de-icing procedures. As Royal Air Maroc did not have a copy of the CAIL procedures in its possession, the captain was not in a position to monitor the work of the de-icing crew. The captain thereby accepted the de-icing of the aircraft but was not familiar with the de-icing procedures being used. 2.5 Training in Engines-On De-icing Examination of the electronic mail between the Manager, System Aircraft De-icing, the Manager of Client Services at Mirabel, and the instructor/developer prior to 03January 1995 revealed that the need for the engines-on de-icing course was somewhat urgent in order to satisfy client demand and to compete against other de-icing companies. The course given on 03January 1995 was different from that given by CAIL for engines-on de-icing of the Boeing737 and Airbus 320. The test on the theoretical portion, which is normally required, had not been devised for the course given on 03January 1995, and the procedures for the Boeing 727 and Lockheed 1011 had not been developed. The practical engines-on exercise was not conducted on the aircraft covered in the classroom; instead, an Airbus 310 was used, an aircraft on which the employees had not been trained, and which they were not authorized to de-ice with the engines running. It is possible that the course created some confusion for the employees as to which aircraft they were required to de-ice with engines off and which they could de-ice with engines running. Some employees mistakenly thought they were authorized to de-ice Boeing 747 aircraft with the engines running. Contradictory testimony regarding the conduct of the course precluded a determination as to whether the employees had been told that they could de-ice Boeing 747s with the engines running. But correspondence between the instructor/developer and the System De-icing Program Manager indicates that the employees were not qualified to de-ice Boeing 747s with the engines on. Further, Snowman1 had attended a de-icing course supported by an appropriate manual in which it was stated that de-icing an aircraft while its engines were running was not authorized unless the employee was trained to do so. As he had not attended any engines-on de-icing course, he had no reason to believe he was authorized by CAIL to de-ice an aircraft with its engines running. 2.6 Competition Between De-icing Contractors Seven companies were authorized by ADM to de-ice aircraft according to their practices in the Mirabel airport de-icing centre. Rivalry was especially fierce between the employees of CAIL and those of other private contractors. Several de-icing contractors de-iced all aircraft types with the engines running. As private de-icing contractors were not regulated, they were able to respond quickly to client demands. The regulatory requirements applicable to CAIL, with the attendant requirement to develop procedures and provide training, meant that CAIL, working within the rules, could not provide as fast and ready a service as could the private contractors. This undoubtedly heightened competition between CAIL and private de-icing contractors in their desire for de-icing contracts, and this competition might have led some CAIL employees to take liberties with the established safety standards. When the Royal Air Maroc captain indicated that there would be a delay in starting the de-icing if he had to shut down the engines and start the APU, Snowman1 decided to de-ice the aircraft with the engines running, though he had not taken the necessary engines-on training. He was also aware, having taken the initial de-icing course, that he was not supposed to de-ice an aircraft with its engines running. Some factors that could have influenced his decision were a normal desire to improve the speed and efficiency of de-icing operations and to maximize the use of hold-over times for the de-icing fluid. It is probable that a significant additional factor was the competition between de-icing contractors. 2.7 Control of De-icing Area The apron controller performed his tasks in accordance with established procedures and his assigned responsibilities. He guided the aircraft until it was stopped at the south station. The aircraft came fully under the responsibility of the captain after it was stopped for de-icing. Before issuing taxi instructions to the aircraft, the controller verified that the taxiway was clear. It was not his responsibility to consult the flight crew and de-icing personnel to determine whether the aircraft was clear and ready to taxi. That responsibility was assumed by the captain when the co-pilot declared the aircraft ready to taxi.